Greenshot - Greenshot is a free and open source screenshot tool that allows annotation and highlighting using the built-in image editor.
Capture2text - Capture2Text enables users to quickly OCR a portion of the screen using a keyboard shortcut.
TextSniper - Instantly extract any text from your Mac's screen
ksnip - Ksnip is a Qt based cross-platform screenshot tool that provides many annotation features for your screenshots. - DamirPorobic/ksnip
dpScreenOCR - Program to recognize text on screen
JOCR - Apparently JOCR requires Microsoft Office 2003 or 2007 and won't work with Office 2010 (unless...